1. Technical Field of the Invention
This invention relates to cellular telecommunications networks and, more particularly, to an intelligent mobile station that stores, retrieves, and executes enhanced subscriber services in a cellular telecommunications network.
2. Description of Related Art
In modem telecommunication systems, it has become increasingly important for network operators to be able to provide their subscribers with enhanced subscriber services. These services may include the provision of an 800 Services Database, a Credit Card Verification Database, Geographic Call Routing, Incoming Call Routing, Multi-location Extension Dialing, Network Automatic Call Distribution, Flexible Call Routing, Flexible Carrier Selection, CLASS Calling Name Delivery Database, and others. In wireline telephone systems, such enhanced subscriber services may be provided through an Intelligent Network (IN) (e.g., Bellcore Advanced Intelligent Network (AN) or its CCITT/ITU equivalent: ITUms, CS-1, Q. 1200, etc.).
FIG. 1 is a simplified block diagram of a typical wireline telecommunication system using an IN to provide enhanced subscriber services. The exemplary network in FIG. 1 utilizes a Bellcore AIN. The AIN 12 and its associated Signaling System Number 7 (SS7) protocol are described in the Bellcore recommendation, "TR-NWT-000246, Bell Communications Research Specification of Signaling System Number 7," which is incorporated by reference herein. A large number of Local Switches (LSs) 13a-n may be connected to a Service Switching Point/Tandem (SSP/T) 14 via multi-frequency IF) links 15. A "tandem", as used herein, may be a local, LATA, or access tandem. The LSs 13a-n provide connections for subscribers 16a-n into the telecommunications system 11. The AIN 12 uses a system of high speed telecommunications links known as a Common Channel Signaling (CCS) network which employs the standard SS7 signaling protocol to link all of the components of the AIN 12. Standard telephony diagrams, and FIG. 1 herein, indicate lifiks utilizing the SS7 signaing protocol as dotted lines and MF trunks as solid lines.
The components of the AIN 12 may include the SSP/T 14, one or more Signal Transfer Points (STPs) 18a-n which act as intermediate switching nodes, and one or more Service Control Points (SCPs) 19a-n. The SCPs 19 each contain a database of enhanced subscriber services which are accessed and controlled by a Service Logic Program (SLP). The SCP 19 currently utiiizes a standardized protocol known as Transaction Capabilities Application Part (TCAP) for coordination of functions. The current version of the protocol required for communication with the SCP 19 is TCAP/AMN Release 0.1. The SCP 19 is described in the Bellcore recommendation, "TA-NWT-001280, Advanced Intelligent Network (AIN) Service Control Point (SCP) Generic Requirements," which is incorporated by reference herein. The SCP 19 acts as a repository for enhanced subscriber services which may be accessed by any one of the LSs 13a-n. In the past, each LS had to be individually upgraded with enhanced subscriber services. With the implementation of the AIN 12, and the required communications capabilities in the LSs, new enhanced services need only be added to the SCP 19.
As seen from the above description, intelligent networks have been developed strictly as wireline communication systems. The signaling protocol utilized for intelligent networks allows only for control of telephone network switching elements in response to queries originated by network switching elements. The fixed nature of installed wirelines limits the utilization of intelligent networks. Therefore, following the development of intelligent networks, it was recognized that it would be beneficial for wireless communication systems to be able to access the intelligent networks as well. Systems have been proposed that enable mobile telephone users to access intelligent networks and retrieve enhanced services from the SCP.
One such system is described in U.S. Pat. No. 5,353,331 to Emery et al. (Emery). Emery discloses an integrated wired and wireless communications network that utilizes a SCP in an AIN to store enhanced subscriber services. A mobility controller (MC) is provided to enable access by mobile subscribers in a cellular telecommunications network. The cellular telecommunications network includes a home location register (HLR) which includes a database of subscriber information including location information and subscriber profiles for mobile stations known by that HLR. In Emery, the HLR and the SCP communicate via the TCAP communications protocol.
A major problem with systems such as Emery which integrate wireless communication systems with the existing wireline AIN is that they require that the TCAP protocol be utilized for communication with the SCP and access to enhanced services. It is a very expensive and inefficient process for equipment suppliers in the cellular telecommunications industry to modify their equipment to utilize the TCAP protocol. In addition, the storing of enhanced services in a centralized SCP in a wireline AIN places restrictions on mobile stations and the freedom they have to access enhanced services in the cellular network. There is no known solution to the above mentioned deficiency and shortcoming of existing systems for providing mobile subscribers with enhanced subscriber services.
In another proposed cellular telecommunication system, the functionality of the SCP is implemented in the HLR. All intelligent processing required to deliver calls is performed within the cellular network, in the HLR/SCP. The HLR/SCP locates the subscriber, assesses the subscriber's availability to receive calls, and routes incoming calls to the subscriber's serving MSC. In addition, the HLR/SCP transfers calls to other numbers or locations if call delivery does not succeed on the first attempt or if enhanced services stored in the HLR/SCP direct such call diversion.
In all this process, the HLR/SCP is a controlling, centralized "brain" of the operation. The mobile station is a "slave" to this brain. As a result, if a subscriber desires a particular service that is tailored to the subscriber's individual needs or desires, he must wait for a service provider to implement the service in the HLRISCP. This could mean major delays for the subscriber, or the service may never be implemented at all.
It would be a distinct advantage to have a system which provides mobile subscribers with enhanced subscriber services and does not require access to the wireline AIN or modification of cellular equipment to utiiize the TCAP protocol. Additionally, it would be advantageous for the source of intelligent processing to be decentralized in the cellular network rather than concentrated in the HLR/SCP. This would provided greater freedom to subscribers to customize their own services and implement enhanced services when desired. The present invention provides such a system.